어야 주다

only give it if you

-아/어야 means "only if, not unless," so putting it before 주다 sets a condition on the giving: 얼굴을 봐야 주지 "I'd have to see him before I could give him anything," 최소 20년은 내야 줄게, 혹시 요즘에 어른은 신청을 해야 줘. Several lines are about benefits or money that require you to apply or qualify (이런 거를 다 통과해야 주는 특권이기 때문에). It also works with 있다 to say the precondition simply doesn't exist: 믿을 놈(?)이 있어야 주지 누굴 주겠냐!.

Register: casual, blunt